JACKSON, Mississippi -- The Mississippi Supreme Court wants to know why a trial judge allowed a third statement as evidence after tossing out two others authorities took from a suspect while he was hospitalized and sedated.

The Supreme Court directed the Harrison County Circuit Court to conduct a hearing into whether the third statement -- used as evidence against Jason Lee Keller in his 2009 trial -- was coerced by authorities as the first two were found to be.

Keller was sentenced to die for the 2007 robbery and murder of 41-year-old Hat Nguyen in Harrison County. Prosecutors said the single mother of four was killed at the convenience store she owned. Nguyen was shot four times. Keller, now 33, was convicted in Harrison County Circuit Court in 2009.

In oral arguments in October, Alison Steiner with the Office of Capital Defense Counsel told the Supreme Court that the trial judge previously disallowed two other statements as involuntary because they were taken while Keller was on painkillers.

Steiner said Keller was shot in the chest while being taken into custody.

She said the third interrogation -- a continuation of the earlier ones and taken some 14 hours later -- violated the doctrine of "fruit of the poisonous tree." The doctrine provides that evidence obtained from an illegal, coercive interrogation must be excluded from trial.

Prosecutors said the court record showed Keller signed a waiver and agreed to be interviewed by investigators. Prosecutors said there was no testimony about Keller being impaired by morphine or other drugs.

Justice Josiah D. Coleman, writing in the 7-2 order, said that the trial judge didn't give any rationale when he allowed the third statement as evidence. He said the hearing should determine if law enforcement officials coerced any statement from Keller.

If so, Coleman said the trial judge should decide if anything coerced from Keller was used to glean information from the suspect in a later, lawful questioning.

Coleman said the court was taking this step "to ensure that the trial court's admission of Keller's third statement into evidence did not violate federal or Mississippi constitutional principles."

But Justice Jim Kitchens, joined by Justice Leslie King, argued the court was asking a trial judge to redo a statement suppression conducted and concluded three years ago.

"Years after the relevant events that generated Keller's trial we seek to re-enact or recreate, under this court's direction, a pretrial hearing in a post-trial environment. Once a case has been tried and appealed, the record from the trial court is sacrosanct and unchangeable," Kitchens said.